Question: Simplify the following expression: $\sqrt{18} - \sqrt{8}$
Solution: First, try to factor any perfect squares out of the radicals. $= \sqrt{18} - \sqrt{8}$ $= \sqrt{9 \cdot 2} - \sqrt{4 \cdot 2}$ Separate the radicals and simplify. $= \sqrt{9} \cdot \sqrt{2} - \sqrt{4} \cdot \sqrt{2}$ $= 3\sqrt{2} - 2\sqrt{2}$ Finally, simplify by combining the terms. $= ( 3 - 2 )\sqrt{2} = \sqrt{2}$